Identification of human plasma cells with a lamprey monoclonal antibody
Cuiling Yu, … , Max D. Cooper, Götz R.A. Ehrhardt
Cuiling Yu, … , Max D. Cooper, Götz R.A. Ehrhardt
Published March 17, 2016
Citation Information: JCI Insight. 2016;1(3):e84738. https://doi.org/10.1172/jci.insight.84738.
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Resource and Technical Advance Immunology

Identification of human plasma cells with a lamprey monoclonal antibody

Abstract

Ab-producing plasma cells (PCs) serve as key participants in countering pathogenic challenges as well as being contributors to autoimmune and malignant disorders. Thus far, only a limited number of PC–specific markers have been identified. The characterization of the unique variable lymphocyte receptor (VLR) Abs that are made by evolutionarily distant jawless vertebrates prompted us to investigate whether VLR Abs could detect novel PC antigens that have not been recognized by conventional Abs. Here, we describe a monoclonal lamprey Ab, VLRB MM3, that was raised against primary multiple myeloma cells. VLRB MM3 recognizes a unique epitope of the CD38 ectoenzyme that is present on plasmablasts and PCs from healthy individuals and on most, but not all, multiple myelomas. Binding by the VLRB MM3 Ab coincides with CD38 dimerization and NAD glycohydrolase activity. Our data demonstrate that the lamprey VLRB MM3 Ab is a unique reagent for the identification of plasmablasts and PCs, with potential applications in the diagnosis and therapeutic intervention of PC or autoimmune disorders.

Authors

Cuiling Yu, Yanling Liu, Justin Tze Ho Chan, Jiefei Tong, Zhihua Li, Mengyao Shi, Dariush Davani, Marion Parsons, Srijit Khan, Wei Zhan, Shuya Kyu, Eyal Grunebaum, Paolo Campisi, Evan J. Propst, David L. Jaye, Suzanne Trudel, Michael F. Moran, Mario Ostrowski, Brantley R. Herrin, F. Eun-Hyung Lee, Ignacio Sanz, Max D. Cooper, Götz R.A. Ehrhardt

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Figure 6

VLRB MM3 binding correlates with CD38 enzymatic activity.

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VLRB MM3 binding correlates with CD38 enzymatic activity. (A) VLRB MM3 b...
(A) VLRB MM3 binding to exogenous (BJAB, top panel) and endogenous (Daudi, bottom panel) CD38. BJAB cells were transiently transfected with CD38-EGFP-GyrB fusion constructs, followed by coumermycin treatment (1 μM) in the presence of the nonhydrolyzable inhibitor araF or NAD controls for 40 minutes prior to addition of Abs. VLRB MM3 binding to transfected BJAB cells was assessed for GFP-positive cells corresponding to gate II of Figure 5. Data represent the median fluorescence intensity (n = 4) ± SD, normalized to values obtained for cells without coumermycin treatment. *P < 0.05, by Student’s t test. (B) Assessment of CD38 enzymatic activity following VLRB MM3 treatment in BJAB (top panels) and Daudi (bottom panels) B cells. BJAB cells were transiently transfected with CD38-EGFP-GyrB fusion constructs, followed by isolation of transfected cells and coumermycin treatment. NAD hydrolase activity was assessed and is shown as the ratio of coumermycin-treated cells relative to untreated cells (top, left panel). Coumermycin-treated cells were preincubated with either VLR4 or VLRB MM3 prior to addition of the NAD hydrolase substrate. NAD activity of VLRB-treated cells is shown relative to that of VLR4-treated controls (top, right panel). Statistical significance was determined using a 1-sample Student’s t test (n = 6). Assessment of endogenous CD38 enzymatic activity in Daudi B cells was performed following treatment with monoclonal VLR Abs (left panel) or conventional mAbs (right panel). NAD activity of the treated cells is shown as the ratio relative to the control Ab–treated cells. Statistical significance was determined using a 1-sample Student’s t test (n = 6). araF, β-ara-2′-deoxy-2′-fluoro NAD; CM, coumermycin; MFI, mean fluorescence intensity; norm., normalized; rel., relative; VLRB, variable lymphocyte receptor B.